California hospitals should be prepared to face significant strain from the coronavirus if social distancing measures are lifted, researchers have warned in a new study.

In a study released this week, UC Berkeley School of Public Health and Kaiser Permanente researchers analyzed more than 1,000 hospitalized patients with COVID-19 in California and Washington within the Kaiser system.

The biggest takeaway? Long COVID-19 patient hospital stays — especially for those that don’t ultimately survive — could burden the health system during a spike in cases, particularly if jurisdictions loosen shelter-in-place orders.

“What we’re finding is really extraordinarily long lengths of stay — at least a heavy proportion of people with long lengths of stay — which is where the capacity impact of the health care system becomes so acute,” said Dr. Joe Lewnard, the study’s lead author and assistant professor of epidemiology at Berkeley.

On average, survivors among the 1,277 patients were hospitalized for nearly 10.7 days, and non-survivors for 13.7. That’s much higher than in China, where non-survivors were hospitalized for 7.5 days, researchers wrote, possibly because of less end-of-life care.

The prolonged hospitalizations mean that West Coast hospitals and intensive care units could quickly hit capacity like in Italy and New York — even if they’ve avoided it so far.

“Since we’re so far away from herd immunity — very few people have been affected at this point, based off what we and others are modeling — we’re looking at a similarly dangerous situation after social distancing measures are lifted,” Lewnard said.

In California, officials like Gov. Gavin Newsom have spoken favorably in recent days of flattening the curve due to statewide shelter-in-place orders. In fact, the virus’s reproduction rate — or the number of people that each infected person passed the virus to — had already declined to around 1 in Northern California by March 20, researchers estimate.

Early social distancing measures, from companies encouraging work-from-home policies to banning large gatherings, certainly helped to stem the spread of the disease before Newsom’s March 19 statewide order, researchers said.

“That’s the context people need to remember. It’s not like all our lives changed suddenly with the statewide order,” Lewnard said.

Now that nationwide discussion centers around possible changes to those orders, however, that low transmission rate could quickly skyrocket again, the research team cautioned.

The “great fear,” Lewnard said, is that hospitals will quickly be pummeled with fresh cases and reach capacity if restrictions are lifted wholesale.

“What we have to keep in mind is that these reductions are hard-earned through non-pharmaceutical interventions,” he said. “It would be very unreasonable to expect going back to our pre-epidemic lifestyles.”

Fiona Kelliher is a breaking news reporter at The Mercury News. She previously covered housing and real estate for the San Francisco Business Times. Originally from Minneapolis, she is a fan of almost any food that is fried and eaten on a stick.

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